For example, in the following Patent document 1, it is an object to form the seat sliding device for the vehicle as described above in a compact size, and there is proposed a lock mechanism, which includes a lock lever disposed within sections of both rails, extended longitudinally, assembled in the upper rail to be capable of being tilted, and provided with claws to be capable of being fitted into engaging holes formed on both rails from the inside of both rails toward the outside thereof, a spring member disposed within the sections of both rails for urging the lock lever in its locking direction, and operation means assembled in the upper rail for operating to tilt the lock lever.
Furthermore, in the following Patent document 2, it is an object to position only a middle portion of a spring member relative to a latch lever, without restricting opposite ends of the spring member, and it is proposed to form the spring member like a dogleg-shaped bar, contact its opposite ends with a bent portion of the upper rail, contact the middle portion with a spring hanging portion, provide a pair of holding portions on one of the spring hanging portion and the middle portion of the spring member, and provide engaging portions positioned between the pair of holding portions on the other one of them.    Patent document 1:    Japanese Patent Laid-open Publication No. 2002-154356    Patent document 2:    Japanese Patent Laid-open Publication No. 2005-7982